ABB ACS355 - Page 229

Actual signals and parameters 229
2303 DERIVATION
TIME
Defines the derivation time for the speed controller.
Derivative action boosts the controller output if the error
value changes. The longer the derivation time, the more the
speed controller output is boosted during the change. If the
derivation time is set to zero, the controller works as a PI
controller, otherwise as a PID controller.
The derivation makes the control more responsive for
disturbances.
The figure below shows the speed controller output after an
error step when the error remains constant.
0ms
0.…10000 ms Time 1 = 1 ms
All parameters
No. Name/Value Description Def/FbEq
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time > 0
T
s
= Sample time period = 2 ms
Δe = Error value change between two samples
e = Error value
Controller
output
K
p
·e
%
t
K
p
·e
T
I
Error value
K
p
· T
D
·
Δe
T
s